Device for the mechanical sorting and collecting of veneer sheets of different lengths



June 12, 1962 CARL'HEINZ MULLER 3,038,604

' DEVICE FOR THE MECHANICAL SORTING AND COLLECTING OF V VENEER SHEETS OF DIFFERENT LENGTHS Filed April 19, 1960 3 Sheets-Sheet 1 g "1 11 ll a V E Q Invenior:

June 1962 CARL-HEINZ MULLER 3,038,604

DEVICE FOR THE MECHANICAL. SORTING AND COLLECTING OF VENEER SHEETS OF DIFFERENT LENGTHS' Filed April 19, 1960 3 Sheets-Sheet 2 3,038,604 DEVICE FOR THE MECHANICAL SORTING AND COLLECTING OF June 12, 1962. CARLHEINZ MULLE R VENEER SHEETS OF DIFFERENT 'LENGTHS 5 Sheets-SheeC 3 Filed April 19, 1960 United States Patent DEVICE FOR THE MECHANICAL SORTING AND COLLECTING 0F VENEER SHEETS 0F DIFFER- ENT LENGTHS Carl-Heinz Miiller, Forst, uber Holzminden, Germany Filed Apr. 19, 1960, Ser. No. 23,196

Claims priority, application Germany Apr. 22, 1959 Claims. (Cl. 209-82) The sheets of veneer coming from the shears, which, due to the removal of damaged places, such as branch holes, cracks or the like, are of different lengths, are as a rule removed by hand, sorted and piled in such a manner that the veneer sheets having a length within similar limits will form a pile of these size limits. Such sorting by hand wastes a great deal of time and is also expensive, as it requires a relatively large staff of operating personnel. Moreover, the still moist sensitive sheets are easily damaged when handled carelessly. Also, the limited tempo of sorting by hand reduces the otherwise possible working tempo of the veneer shears, behind which the sheets are moved forward by conveying means to the sorting point. In order to avoid all these disadvantages, that is to enable a quick mechanical sorting of such veneer sheets which will avoid damage to the veneer sheets and require less operators, by depositing the sheets in piles corresponding to the diiterent size limits is the object of the present invention.

This is achieved according to the invention by the con-- cept that in such a conveying means for the veneer sheets, measuring means are mounted between switching members so formed and arranged that when the distance between some of them is at the same time bridged by a veneer sheet moved on the conveying means, control transmission and driving means which actuate closing members of the inlet openings arranged in the conveying means of collecting stations for the reception of veneer sheets of different lengths, which collecting stations are arranged below the conveying means and behind the control members in the direction of conveyance.

Further details of the invention are described below with reference to the diagrammatic drawing illustrating a constructional example.

In the drawing:

FIGURE 1 is a view in side elevation and partly in cross-section of the complete assembly;

FIGURE 2 is a plan view of a detail of a collecting station for veneer sheets;

FIGURE 3. is a plan view of the beginning of a conveying means for the assembly;

FIGURE 4 is a diagrammatic representation of the control elements for operating a closing member of a collecting station; and

FIGURE 5 is a diagrammatic representation on a larger scale of the beginning of a conveying means of the assembly with a closing member for a collecting station and the control elements.

The veneer sheets are fed forward by conveying means such as endless bands, leading from veneer shears (not shown) of which in FIGURE 1 only the end is shown. The continuation of the conveying means 1 is formed by a transfer table 2 provided withan endless conveyer band 3 travelling thereabove. By means of this conveyer band 3 the conveying speed of the veneer sheets fed for- 3,038,604 Patented June 12, 1962 ice ward by the conveying means 1 is considerably accelerated for materially increasing the distance between the rear edge of a veneer sheet which is leaving the conveyer band 3, from the forward edge of a veneer sheet following such sheet and which is still supported by the conveying means 1, so that for each veneer sheet there will be sufficient time interval for measuring the sheet and,

through such measuring, to bring about the hereinafter described procedures.

The conveyer band 3 or the transfer table 2 is followed by a conveyer means for the veneer sheets which is formed by an endless conveyer band 4, fixed transfer tables 5 and 6 and an endless conveyer band 7 which with its lower run rests on the upper run of the conveyer band 4 and on the transfer tables 5 and 6.

The upper run of the conveyer band 4 is guided in a convex path by passing over rollers 4a and the lower run of the conveyer band 7 corresponds to the path of the upper run of band 4 (FIG. 1). Similarly the two transfer tables 5 and 6 are provided with a convex upper surface and slotted in the manner of grid rollers 6a which are mounted to rotate below the tables 5 and 6 project through the spaces in the grid into the table surface to enable the veneer sheets to be pushed along with rolling friction over these tables. On these curved surfaces of the tables or their rollers rests the lower run of the conveyor band 7.

By these convexly curved conveying surfaces a frictionclosed contact on the conveyer band 4 and the rollers 6a or the tables 5, 6 is effected positively by the lower run of the conveyer band 7 which presses the veneer-sheets on to these surfaces. A motor M functions to maintain at least the conveyer bands 3 and 7 in constant rotation about their end rollers, whereas the conveyer band 4 may be carried along through friction engagement with the conveyer band 7.

In a forward section of the conveying track, namely at least within the range of the conveyer band 4, there are provided control members 8, 9, 10 so arranged that the veneer sheets moved on the conveying track can bridge the space between at least two of these control members. By this means, the control operations hereinafter described are released in that the still moist veneer sheets acting as electric conductors connect electrically with one another, two control members and thereby control conveying and driving means for closing members, as hereinafter described.

The control members define between one another measuring ranges which determine the limit sizes of the veneer sheets moving along beneath such members on the conveying means and, according to the measuring result in each case, cut-in and cut-out those driving and transmitting arrangements by which the particular veneer sheet measure reaches the collecting station, for such particular length dimension.

The constructional example of the invention illustrated includes three such collecting stations 12, 13, 14. There could however be a lesser or greater number of such collecting places behind one another and correspondingly lesser or greater number of control members would be provided in the correspondingly dimensioned conveying section (conveyer band 4) of the conveying means.

The collecting stations 12, 13, 14 are arranged below that conveying section of the conveyer means, which follows, seen in the direction of movement of the sheets, the

conveyer track section in which the control members 8 to 10 are arranged. The sequence is such that on each station for piling veneer sheets of a certain size limit there follows a collecting station of the next greater size limit.

Other than the last or terminal collecting station 14, the remaining collecting stations 12, and 13 as illustrated are covered by the transfer tables 5 and 6 which at their forward transverse edge leave free an entrance aperture 15' or 16 respectively for the veneer sheets into the particular collecting station 12 or 13. In the illustrated example, these entrance apertures are adapted to be closed by flaplike closing members 17 and 18 respectively. These closing members 17 and 18 are shown in the drawing normally in their open position.

The closing members are controlled in the following manner by the cut veneer pieces moving on the conveyer means:

Should a veneer sheet arriving at the forward conveyer means section (conveyer belt 4) be shorter than the measured space formed by the distance between the control members 8 and 9, then all closing members 17, 13 will remain in the open position so that the particular veneer sheet will pass into the collecting station 12 lying nearest to the member 8. Should a veneer sheet be so long that it bridges over the space between members 8 and 9, but is shorter than the space between members 3 and 10, it will provide an electrically conducting connection between the members 8 and 9, whereby the closing member 17 is moved in the manner described hereinafter in connection with FIGURE 4 into its position in which it closes the entrance aperture 15 of the collecting station 12 so that the veneer sheet initiating this procedure will move over the collecting station 12 into the open collecting station 13.

Should a veneer sheet be so long that it bridges the space between members 8 and 10, it will then form an electrically conducting connection between the members 8, 9 and 10. Thus, by means of the suitable transmission and driving means the closing member 17 of the collecting station 12 and the member 18 of the collecting station 13 will be simultaneously closed, whereby the veneer sheet which initiates this control operation and moves along on the conveying means moves into the collecting station 14- and so on, if there are still further collecting stations.

When, as in the example shown, the collecting station 14 is the last of a series of collecting stations disposed one behind the other, then a member 19 which is identical with closing members 17 and 18 will function at the entrance to this collecting station exclusively only for guiding the veneer sheet into these collecting stations.

As soon as a veneer sheet has moved with its forward edge past the closing member 17 or 17 and 18, which happens to be in the closed position, it will control by the way of a contact 60 or a contact 60 and 60a the hereinafter described control circuits, whereby the closing members 17 or 17 and 18 will be immediately moved back into their open position shown in FIGURE 1 so that they will be again ready for control by a following veneer sheet. The control means suitable for this purpose are also described hereinafter with reference to FIGURE 4 for one of the closing members.

In order to be able automatically to sort out specially short veneer sheet pieces, for instance those containing blemishes, such as branch holes, cracks or the like as useless waste before they reach one of the collecting stations 12 to 14, the following arrangement is provided:

Above the end of the conveying means 1 two control members in the form of photo cells 106 and 107 of a type known per se are arranged in a spaced relationship, which is slightly greater than the waste veneer pieces to be removed to a collecting station, for instance a mobile container 23 and opposite to said photo cells and below the conveying means 1, two sources of light 101 and 102, respectively, are mounted. The light beam emanating from these sources may pass the conveying means 1 and elk 4 strike the photo cells 106 and 107, respectively. This is due to the fact that the conveying means consists of narrow, separated endless bands (FIG. 3) and the light beams can pass through the spaces between the bands.

The transfer table 2 between the conveying means 1 and 4, which has already been alluded to is normally in a position, in which the waste veneer pieces conveyed by the conveying means, would fall into the waste collecting container 23. This position corresponds to the operative stage which will be further described below with reference to FIGURE 5.

All veneer sheets which are longer than the space between the photo cells 106 and 107 will interrupt the path of the rays of the two sources of light. This interruption simultaneously causes a switching operation for swinging the transfer table 2 into the plane of the conveying surface of the conveying means 1 about pivotal point 22 so that the veneer sheets move on over the table 2 on the conveying means and be measured on the conveying track section (band 4), for the purposes referred to above.

Should the veneer sheets be shorter than the space between the two photo cells 106 and 107, the eight beams of the two sources of light 101 and 102 will, when the piece of veneer is between them, not be interrupted simultaneously. Consequently, as will be explained below, the transfer table 2 which is in its open position will not be turned out of the position shown in FIGURE 1 into the conveying plane of the conveying means 1, so that the piece of veneer in question will fall as waste into the container 23.

The control members 8, 9, 10 may be made displaceable and fixable on their carriers T in such a manner that their distance from one another can be altered or adjusted according to the requirements of the measuring lengths desired in each particular case.

As the transfer and driving means for each of the closing members 17 and 18 are similar in structural detail, it will suflice, for an understanding to describe the switching arrangement for one of these closing members. In FIGURE 4 these means are illustrated for the closing member *17 of the collecting station 12. In accordance therewith, a thyratron tube 57 receives its anode voltage from the positive pole of a battery 58' by way of conductor 59, interrupting contact 60, conductor 61, solenoid 54 and conductor 62. Grid 63 of the thyratron tube 57 is connected by way of a resistance 64 with negative pole 65 of the battery 58. Tapping 66 of the battery 58 in connected by way of conductor 67 with cathode 68 of the thyratron tube 57. A battery 69 supplies the heating voltage for the cathode 68 of the thyratron tube 57. The grid 63 of the thyratron tube 57 is connected by way of conductor 70 with the control member 9. The tapping 66 of the battery 58 is connected by way of the conductor 71 with the control member 8.

As soon as a veneer sheet P which in consequence of its moisture is electrically conductive connects the control member 8 and the control member 9 conductively with one another, a current will flow from the tapping 66 of the battery 58 through the conductor 71, the control member 8 through the veneer sheet F, the control member 9, the conductor 70 and the resistance 64 to the negative pole 65 of the battery 58. By this means the negative voltage acting at the grid 63 of the thyratron tube 57 and fed by way of the resistance 64 to the negaactuated and a pressure medium flows from a compressor (not shown) by way of pipe line 56, the magnetic valve 53 and pipe line 52 into cylinder 51 and closes by way of a lever 50 the closing member 17 of the collecting station 12. As soon as the veneer sheet F, which now can pass over to the table has opened the interrupted contact 60 which is located behind the closing member 17 above the conveying means by means of its forward edge, the flow of the anode current of the thyratron tube 57 will be interrupted, the magnetic field of the solenoid 54 reduced and thereby the pressure in the pressure cylinder 51 suspended, so that the closing member 17 will under the action of its dead weight move into the open position.

In order that the veneer sheets shall be deposited in the collecting stations 12 to 14 parallel to their bottom and shall not when being pushed into the collecting station, be deposited in an entirely or partially rolled up state, two precautionary measures are adopted. In the first place the bottom of each collecting station is formed by a raisable platform 24, 25 and 26 respectively and each platform is made capable of being raised and lowered by lifting means. For instance, as shown in FIGURE 1, the same includes piston and cylinder means 27, 28, 29 connected to a pipe D for a pressure medium, such that the falling distance of a veneer sheet moving into the collecting station is made as small as possible. The raised lifting platform is generally sunk in accordance with the pile of veneer sheets building up thereon which can be brought about for instance by actuating valves H. Each platform of the lifting platforms 24, 25, 26 may be so constructed that the pile of veneer sheets is formed on a collecting member for instance a frame or plate 30, 31, 32 and can be lifted off the platform by stackers together with the frame or plate.

The second means for ensuring a position of the veneer sheets parallel to the bottom of the collecting station consists of a depositing platform which is disposed in the collecting stations immediately below the entrance aperture or 16 or the member 19 for the veneer sheet into the collecting stations 12, 13, 14. The depositing platform consists of two rails 45, 46 which are capable of being moved in opposite directions and which can be moved away from one another in such a manner that a veneer sheet lying on the same loses its support and will fall on to the frame or plate 30, 31 or 32 lying immediately beneath.

'A stop 47, 48 or 49 limits the movement of the veneer sheet when being pushed into the collecting station. A rockable contact lever a, 2012 or 200 which is located immediately in front of these stops is actuated by the veneer sheet as it is pushed in by closing the contact. The switching operation immediately following may be seen by referring to FIGURE 2 for the collecting station 12. Thereupon, after closing the contact lever 20a a current will flow from battery 21 by way of conductors 151. By this means solenoids 152 are actuated and operate magnetic valves 153 which reverse the direction of the pressure medium acting in pressure cylinders 35, 36 from pressure medium pipe 155 into pressure medium pipe 156 whereby the pressure medium in the cylinder 35, 36 is introduced so that it displaces pistons 154 slidable in the said cylinders outwardly. Since, as shown in FIGURE 2, these pistons are connected with the rails 45 and 46 forming the depositing platform, these rails will be displaced away from one another whereby, as mentioned above, the veneer sheet lying on the same looses its support. By this means the contact lever 20a is again opened and the said circuit is reopened, whereby the magnetic valves 153 are returned into their initial position and the pressure medium again enters the cylinders 35, 36 on the opposite side of the pistons 164 and thereby moves the pistons towards one another whereby the rails 45, 46 connected therewith will also be'moved again towards one another for receiving the next veneer sheet. The pressure medium is supplied from a compressor (not shown) through the pipes D and D=-.

As the width of such veneer sheets is variable, it appears advisable to make the supporting distance of the rails 45 and 46 with respect to one another adjustable. For this purpose, the cylinders 35 and 36 are fixed on girders and 41 which slide on pipes 37 and 38 of frame 39 of the collecting station 12, 13 or 14 respectively and can be fixed by screws 44 in any position to which they are displaced.

To the girders 40, 41 the previously mentioned magnetic valves 153 are fixed. The pressure medium pipes l) which form a connection between the magnetic valves 153 and the main pipe D for the pressure medium must of course be made in the nature of hose-pipes and the like, to allow for the adjusting motions of the two girders 40 and 41.

The above-mentioned transmission and driving means for actuating the transfer table 2 are shown in FIG- URE 5.

Primary winding 75 of a transformer 76 receives its network voltage by way. of conductors 77 and '78. A secondary winding 79 of the said transformer supplies by way of conductors 80 and 81 the heating voltage to tubes 82, $3, 84 and 85. Another secondary winding 86 of a third photo cell 136 supplies by way of conductors 87 and 33 the heating voltage for a rectifier tube 89. A

further secondary winding 90 of the transformer 76 supplies by Way of conductors 91 and 92 the voltage for anodes 93 and 94 of the retifier tube 89. By this means there is produced between the conductors 95 and 96 a direct current voltage which is required for providing current to the tubes 82, 84, 35. From another secondary winding 97 of the transformer 76 the anode voltage for the tube 83 is taken by way of a further conductor 98 and rectifier 99. From secondary winding 100 of the said transformer the normal-running potential is supplied to the sources of light 101, 102 by way of conductors 104 and 105.

The third photo cell 1'36 is arranged with its source of light 103 in the region of the transfer table 2 that is located with regard to the position of the above-menttioned two photo cells 106 and 107 on the other side of the pivotal point 22 of the transfer table 2. It is assumed that the veneeer sheet F shown in FIG. 5 is shorter than the distance between the photo cells 106 and 107. Another veneer sheet F is longer than the distance between the photo cells 106 and 107. -All veneer sheets which, like the veneer sheet F, are shorter than the distance between the photo cells 106 and 107 release no functions of the arrangement and travel unhindered below the obliquely raised transfer table into the waste container 23.

As soon as the forward edge of veneer sheet F has passed the photo cell 106, the beam of light from the source of light 101 to the photo cell 106 is interrupted. By this means the current flowing from the conductor 95 by way of resistance 108, conductor 109, the photo cell 106, conductor 110 to the negative pole 96 of the secondary winding of the transformer 76 is reduced, whereby the voltage connected to grid 111 of the tube 83 is increased. As soon as the veneer sheet F also interrupts the beam of light of the source of light 102 on to the photo cell 107, the flow of current from the conductor 95 by way of a resistance 112, a conductor 113, the photo cell 107, a conductor 114, a resistance 115, a resistance 116, a resistance 117, to the conductor 96 will be diminished. This causes the voltage to grid 118 of the tube 82 to be reduced. Thus, the voltage at the grid 118 of the tube 82 will drop and the voltage from the conductor 95 over a resistance 119 at anode 120 of the tube 82 increases. Consequently, a charging current flows from the anode 120 of the tube 82 by way of a condenser 121 to the grid 111 of the tube 83. The voltage from the conductor 95 connected by way of a resistance 122 to the grid 111 of the tube 83 is raised to such an extent by charging current that the gas-filled thyratron tube 83 ignites and a current flows from the secondary winding 97 of the transformer 76 by Way of the conductor 98, the rectifier 99, contact 123 of a relay 124, a conductor 125, the solenoid 126 or solenoid valve 131, a conductor 127, anode 128 of the tube 83, by way of cathode 129 to negative pole 130 of the secondary winding 97 of the network transformer 76. The current through the solenoid 126 causes the changeover of the solenoid valve 131, whereby the pressure medium will flow from a pipe 132 connected to the compressor pipe D through the solenoid valve 131 by way of a pipe 133 into a pressure cylinder 134 and moves the piston of the latter in the direction of the arrow. The piston rod is connected to a lever 135 so that the latter will be rocked about the pivot 22 and the transfer table 2 which is connected to the lever 135 will be likewise rocked about the pivot 22 into the conveying plane of the conveying means 1. Consequently a veneer sheet F will pass from the conveyer band 1 across the transfer table 2 on to the conveyer band 4.

At the same time the said veneer sheet F passes the photo cell 136 and interrupts the beam of light of the lamp 103 striking the photo cell 136. Through this action, the current flowing from the conductor 95 by way of resistance 137, conductor 138, the photo cell 136, the conductor 110 to the negative pole 96 becomes reduced, whereby the voltage in point 139 of the resistance 137 increases. Consequently, a charging current flows by way of a condenser 140, a resistance 141 to the conductor 13%, so that the voltage at grid 142 of the tube 84 increases. This also causes the anode current flowing through the tube 84 to increase, so that the anode voltage from the conductor 95 by way of a resistance 143 at anode 144 of the tube 84 decreases. Thus, the charge of a condenser 145, which however does not yet have any further function, changes. As soon as the rear edge of the veneer sheet F again allows the light from the source of light 103 to strike the photo cell 136, the current coming from the conductor 95 by way of the resistance 137, the conductor 138, the photo cell 136, the conductor 110 and flowing to the negative pole 96 will increase. Thereby the voltage in the point 139 of the resistance 137 is reduced and a charging current will flow from the conductor 139 by way of resistance 141, condenser 140 to the point 139 of the resistance 137, which for a moment causes the voltage at the grid 142 of the tube 48 to drop. This causes the current flowing from the conductor 95, by way of the resistance 143 through the tube 48 to change, so that the voltage connected to the anode 144 of the tube 84 increases and a charging current will flow fromv the anode 144 of the tube 84 by way of condenser 145, resistance 146 and the resistance 117 to the negative pole 96. This changing current causes an increase in the voltage at grid 147 of the gas-filled tube 85 and brings about the ignition of the tube. A current will therefore flow from the conductor 95 by way of the resistance 117, the coil of relay 124, through the tube 85 and conductor 148 to the negative pole of the secondary winding 97 of the transformer 76. Contact 123 of the relay 124 is thereby interrupted and the current will flow from the secondary winding 97 of the transformer 76, the conductor 98, the rectifier 99, the contact 123 of the relay 124, conductor 125, the solenoid 126, the conductor 127, through the gasfilled tube 83 and the conductor 130 to the negative pole of the scondary winding 97 of the transformer 76. The solenoid valve 131 therefore returns into the initial position shown in the figure. Through this the pipe 133 of the pressure cylinder 134 will be opened, so that the pressure medium on this side of the piston in the cylinder 134, for instance compressed air, passes over the open front side of the solenoid valve 131 into the atmosphere. At the same time a pipe 149 is connected with the main pressure line D of a compressor by way of the pipe 132 and the solenoid valve 131, so that the pressure medium can act on the other side of the said piston in the pressure cylinder 34. By this means the said piston becomes displaced and the lever connected with it and along with the latter the transfer table 2 is rocked back about the pivotal point 22 into the inclined position shown.

Through the flow of current from the conductor 95 by way of the resistance 147, the relay 124, the gas-filled tube 35 and the conductor 148 to the negative pole of the secondary winding 97 of the transformer 76 the voltage at the anode 150 of the gas-filled tube 85 becomes reduced until it lies below the ignition voltage. The ignition of the gas-filled tube 85 thereby becomes extinguished. the anode current flow is interrupted and the contact 123 of the relay 124 returns into the initial position shown in the drawing.

I claim:

1. In a machine for sorting and collecting veneer sheets of different lengths comprising a conveying track for the veneer sheets, a length testing means having a plurality of testing members adjacent to said conveying track, said members being arranged in the conveying direction of said conveying track one behind the other at a predetermined distance so that at least two of said testing members form therebetween a measuring section for said veneer sheets, at least two collecting stations for veneer sheets of different length arranged in the conveying direction of said conveying track in a row behind said testing member and below said conveying track, said conveying track having openings each of which leads to one of said collecting stations, and a movable closing member for each of said openings, with the movement of which closing members being controlled by said length testing means in dependence of the veneer sheet length tested by said testing means, the improvements including a conveying surface for said conveying track being at least within the regions of said length testing means and said collecting stations provided with a convex curve in the conveying direction, and an endless and continuously running conveying means provided above said conveying track, the lower run of said conveying means being guided in such a manner as to closely fit the convex curvature of the conveying surface of said conveying track and to press with friction the veneer sheets against such surface.

2. In a machine as defined in claim 1, in which each of said collecting stations comprises a bottom adapted to be raised and lowered, driving means for raising and lowering said bottom, a depositing platform for a veneer sheet entering said station through said opening in said conveying track, said platform being arranged parallel to said bottom and immediately below said opening in said conveyin track and consisting of two supporting rails arranged to be movable in a common plane in opposite directions, driving means for moving said supporting rails, and a control member arranged between said supporting rails so as to be actuated by the veneer sheet moving through said opening into said collecting station, said control member being adapted to control said driving means so that upon actuation of said control member, said supporting members are moved away from one another for releasing said supported veneer sheet and are moved back into their supporting position when said veneer sheet has fallen on said bottom of said collecting station.

3. In a machine as defined in claim 1, in which each of said collecting stations comprises a bottom. adapted to be raised and lowered, and driving means for raising the bottom to a point immediately below the opening in the conveying track for receiving a veneer sheet with the bottom being lowered by the veneer sheets placed thereon.

4. In a machine as claimed in claim 1, in which each of said collecting stations includes a bottom, a depositing platform immediately below the opening in the conveying track for a veneer sheet entering said opening, the platform being arranged parallel to the bottom, said platform including two supporting members capable of movement in opposite directions, driving means for moving said two supporting members, a control member so arranged as to be actuated by the veneer sheet moving through the 9 10 opening with said control member being adapted to control lecting station on which the girder means is displaceable, said driving means so that upon actuation of the control and screw means for fixing said girder means in position.

member, the supporting members are moved away from one another for releasing the supported veneer sheet and References Cited in the file of this atent are moved back to their supporting position when the 5 p veneer sheet has fallen onto said bottom. UNITED STATES PATENTS 5. In a machine as claimed in claim 4, including girder 2,138,645 Rey Nov. 29, 1938 means for supporting said two supporting members, con- 2,291,261 Taylor July 28, 1942 trol member and driving means, guide means in the col- 2,933,185 Coleman Apr. 19, 1960 

